This invention relates generally to registration of indicia bearing material relative to a tool to be employed in an operation or series of operations on the material and more particularly to optical sensor means for sensing the indicia, a material positioning system and a control system responsive to the output of the sensor to direct the positioning system to establish the indicia bearing material relative to the sensor.
In many machining operations it is necessary to accurately position decorated or indicia bearing material in a machining area for subsequent punching, drilling, machining, hot stamping, or component mounting. The purpose of the positioning is to provide accurate register between the decorated pattern or indicia pattern on materials such as credits cards, nameplates, printed circuit boards or previously partially fabricated materials and a tool or tools for a machining operation.
In addition, each of these operations may be repeated on one piece of material. This can require complex motion control in both the gross, or approximate, positioning and in the final accurate, or pattern register, positioning.
There are other material positioning applications which only require accurate control of the edge of the material in a machining area plus accurate control of material advance. Where this is the case, pattern registration is not required.
Register errors between indicias or patterns on material and pre-pierced register holes or edges can be generated many ways. Four of the most common sources of register errors are:
(1) Dimensional changes in the material during processing after the indicia or pattern is affixed on the material. PA1 (2) Incorrect original positioning of the indicia or pattern on the material. PA1 (3) Accumulated errors when recording multiple patterns on a single piece of material due to errors in generating original artwork. PA1 (4) Changes in material dimensions due to machining.
When accurately positioning decorated material for machining it is often necessary to correct for these or other register errors that have previously occurred in the process. This requires sensing the position of a known feature of the pattern and positioning the patterned material relative to the machining position in response to the sensed pattern feature position.
The sensing of the pattern and control of the material location can be accomplished visually with optical aids and manual controls, or an optical or other pattern sensor can be used to control servo systems to automatically register the pattern
Another source of system errors that can be imposed by the needs of the machining process is the frequently encountered requirement for sensing the pattern with the material in one position, and then moving the material to another position for machining. Another system requirement can be the need for high speed loading and unloading of the material.
The inventive equipment which simultaneously solves the foregoing and other register problems and operates within the limits of these requirements or needs, comprises an inventive optical pattern brightness detector, an inventive material moving mechanism, and an inventive computer based control system.
The inventive optical pattern brightness detector comprises a unique arrangement of illumination source, optical elements and sensing elements which provides in one device precise brightness sensing on both reflective and diffuse surfaces with no parallax errors, a well defined sensing area, and a large separation between the detector sensor body and the decorated material being sensed. These attributes are important when the material surface characteristics, its thickness, and its smoothness vary widely The detector sends pulsed data indicative of the pattern edges in the sensing area on the patterned material to the inventive computer control system as the material moves past the sensing area.
The inventive material moving mechanism comprises a servo drive motor, an encoder, and material control rollers uniquely arranged to accurately sense and control the movement of decorated material during positioning while also allowing for high speed material loading and unloading. In some applications a pair of inventive material moving mechanisms are used. This allows complete control of short strips or sheets of decorated material in a machining area with no part of the paired mechanisms being located in the machining area.
The inventive computer based control system combines the material movement data from the encoder or encoders with pattern edge position pulses from the pattern brightness detector or detectors. The control system generates single axis servo motor control signals for high speed precision register positioning of the decorated material in the machining area. This precision register positioning in the machining area can be accomplished with no part of the inventive equipment located in the machining area. The system also generates signals required to initiate the machining operations sequence after the material is positioned, or before the material is positioned but timed so the actual machining operation occurs after the material is positioned
When the inventive combination of pattern edge detector, material moving mechanism and control system are used to detect a particular type of target on the decorated material the system can generate 2-axis high speed servo motor control signals
Various sensing devices and material positioning systems have been devised to perform tasks analogous to those of the inventive system. In particular, the Jallais U.S. Pat. No. 3,714,447 describes an apparatus for the photo-optical reading of the marks and perforations on record media; the Kissinger U.S. Pat. No. 3,940,608 describes a fiber optic displacement measuring apparatus and the Kessler, et al, U.S. Pat. No. 3,584,779 describes an optical data reading system. Additionally, the Papsdorf U.S. Pat. No. 3,957,188 describes a punched tape control system and the Schulze, et al, U.S. Pat. No. 4,398,657 describes a feeding device for the cyclic feeding of rod or tape like material in presses, cutters and the like.
While each of the foregoing enumerated devices and others have attacked various parts of the indicia pattern location, movement of the indicia or pattern and control of the two in conjunction with one or more machining operations, none have attempted to provide them in a single device and system, nor have they achieved the positioning accuracy necessary to meet contemporary standards.